Rikki Clarke skips - maybe not skips, ambles - down the wicket to Joe Denly. Surrey's run rate is over 11. In the previous over, Clarke put a spinner into the crowd, and now Surrey need only 39 from 44 balls.

When Clarke comes down the wicket, it doesn't seem important, but the interesting thing about T20 is how important one ball can be. Clarke makes one major mistake in the game, on the 46th ball he has been involved in.

Allrounders have the most opportunities in T20 games. The top 20 players in terms of balls they are involved in per match (bowled and faced) is completely composed of players with two skills. Part of this is because when T20 started, we looked more at the skills than the roles. There are plenty of T20 allrounders who are really only good enough at one skill, but they make teams feel better about their line-up or options. At his best, Clarke was a proper allrounder, a front-line batsman and bowler.

On average he bowls 13 balls a game and bats for 11.5, meaning he has 24.5 balls per match. It means he's involved in 10% of the match, but that's not including his fielding.

It is fielding where he first touches the ball in this match.

The first ball that Clarke will field is at point. Two balls later he's in the action again. A more agile fielder stops it. While Clarke is one of the best slip fielders on the county circuit, he's no longer the great young athlete he once was. He doesn't seem a natural fit at point. Other than Morne Morkel, there is no real fielder Surrey need to hide. For the other end, Clarke is at mid-on. A mishit goes over his head. He takes a while to turn, but it doesn't cost Surrey a run.

For the fifth over, Clarke comes on to bowl. His first ball is full on middle and leg, with short fine-leg up. It should have been flicked for runs, instead it ends up feet from being caught by the man in the circle. The next ball is short and at a moving Denly, who knocks it behind square for a boundary. The next three deliveries are slower balls. Denly and Heino Kuhn take two singles. For the last ball, with Denly back on strike, there are a few field moves to strengthen the leg side. Denly places the ball in a new hole on the off side to take a single. Kent have scored seven off the over, a win for Clarke.

Over the last two years he has bowled 66% of his overs in the Powerplay. There's a good reason for it - he has taken his wickets there at under 19 and his economy is 5.4.

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Clarke is back at mid-on. He's slow to see that the batsmen want to take a single and he costs his team one. But in the same over a terrible throw comes in and he is very attentive in his backing up, which saves his team four overthrows.

For the first over after the Powerplay, he tries a mix of slower balls and full pace. He was quick in his prime, and now he still has enough pace to keep a batsman honest. When he bowls a slower ball, it's loopy and slow, possibly bowled out of the back of the hand, going by the way the batsmen are beaten as much by the dip as the pace. A single is mistimed because of this; another is scooped safely towards mid-off. The batsmen can't get on top of him, so towards the end of the over they push hard for two. There is brief confusion and almost a run-out. Four good balls brought about that pressure. Kent take six off the over.

Clarke is moved to short cover. The ball reaches him a few times - routine stops. But on one, Denly and Kuhn scamper through for a single. Clarke scrambles over to the ball and then does a near blind turn to throw at the bowler's end. A few minutes earlier he had saved overthrows; now he gives one away. And while the throw isn't perfect, the overthrow is less to do with him and more to do with Surrey not being alert to the run-out chance.

"Clarke was quick in his prime, and now he still has enough pace to keep a batsman honest. When he bowls a slower ball, it's loopy and slow, possibly bowled out of the back of the hand, going by the way the batsmen are beaten as much by the dip as the pace"

It's clear after two straight overs from Clarke that the batsmen want to take him on. Kuhn gives himself room and smashes a short-of-length ball out to deep cover, where it's stopped by the sweeper. The next ball is a slower ball that confuses Denly, but it slips down leg for a wide. Clarke gets away with a juicy half-volley for a dot ball. The next ball he bowls a good fast ball at the body. Kent only manage a leg-bye.

Denly is seeing them well, but he has struggled to get Clarke away. In eight balls he has taken only eight runs, while at the other end, he has 33 from 21 balls. He goes at Clarke again - it's another slower ball, and he scoops it back over Clarke's head. They scamper two. Next ball, Clarke puts more pace on it. Denly pulls and gets it away for only the second boundary off Clarke's three overs. That is all Clarke will bowl. He has bowled nine slower balls (one a wide) and ten full-paced balls.

Out in the field, he finds himself at mid-off or long-off for much of the rest of the innings. Twice he's doubled over, catching his breath. For some wickets, he takes a chance to catch his breath and doesn't come in to celebrate them, even when one's caught not far from him, out at long-on. He doesn't seem to cost Surrey many runs, maybe one or two, although he doesn't always pick up the ball that quick. Then a drive is smashed to his left - one of Ravi Shastri's tracer bullets. Clarke dives, but he's not close enough to the ball at any point. A quicker, younger fielder stops it. Not long after, Clarke sprints in to restrict the second run brilliantly.

The last ball of the innings is hit out to him hard and straight, but he never looks like stopping the two. When he throws the ball, it doesn't come out of his hand right; it dribbles back to the bowler's end as Kent complete their two.

Kent have made 173. Denly made 102 at a strike rate of 161. The rest of Kent scored at a strike rate of 124. Considering that, it was an under-par score.

Surrey lose their second wicket after 8.2 overs, when they had already made 98, well more than half the chase. Clarke doesn't come in at the fall of the second wicket. In his career of 133 innings, he has only batted 24 of them outside the middle order. In the last three years he has mostly batted at five. The way Surrey are going, it's not clear if he'll be needed, but when Ollie Pope is out, Clarke comes in with Surrey needing 65 at marginally more than a run a ball.

The game seems over. Surrey's fans sing "Football's Coming Home", and the Kent fans, so excited by Denly, are very quiet.

At The Oval, Joe Denly made a hundred and took a hat-trick in Kent's six-run win over Surrey in the T20 Blast Getty Images

Ben Foakes is at 42 off 24 when Clarke enters, so Clarke pushes around some singles, using the gaps on the leg side. He is facing Imran Qayyum's left-arm orthodox and Denly's long-forgotten legspin.

Denly is usually involved in 23 balls per match, 22 as decent opener and one as a bowler. Unlike Clarke, he is not a conventional allrounder. Back in 2010, cricket commentator Nigel Henderson wrote about Denly and his legspin, saying it was a shame Denly had all but given up a skill worth pursuing. It happens a lot at the professional level - David Warner, Steven Smith and Shivnarine Chanderpaul all gave up legspin to focus on batting. When Colin Ingram turned up at Glamorgan, he had turned himself into a keeper despite having started out as a legspinner.

For T20, many players, like Ingram and Denly, are bringing back their childhood potential. For a T20 team, having more options with their bowling, especially among their top-order players, allows them to be more flexible. Opening batsmen who can bowl have the ability to have the most significant impact on a game - they can face the most balls and also bowl 24 of them. Meaning, on average, a strong opener who is a front-line bowler can be involved in upwards of 40 deliveries a game.

Denly hasn't been that. In 178 T20s before this one at The Oval, he has bowled 19 overs. But the week before, in the Royal London 50-over final at Lord's, he took 4 for 57 and was the best bowler for Kent.

In T20, legspinners have taken over because of their ability to turn the ball even on flat pitches, their unpredictability, and the fact that they can spin the ball both ways. Denly's legspin is not revolutionary, but he has the necessary skills. In this situation against a spinner like Denly, it should be easy enough to knock him around for singles.

After six deliveries of pushing the ball around, Clarke attacks, but not Denly. It's Qayyum he hits into the members over long-on. The next ball he faces is from Denly. This is the ball in which he ambles down the wicket. He is nowhere near the ball. It's premeditated but also half-committed. The ball drops short of him. He flings his hands out but misses and the keeper takes the bails off. Clarke is miles out.

This is a regular game for Clarke. He averages 13 balls a game as a bowler; in this one he bowled 18, but his economy was 7.33, which is almost identical to his career rate of 7.29. Perhaps he should have bowled his extra over in the Powerplay. He didn't take a wicket; he takes one on average every 19.5 balls. But Kent's total was still under par on this wicket. His fielding saved runs sometimes and let through a couple of other times, but was about par and better than you'd expect from the average 36-year-old. In total, Clarke was involved in 46 balls (including his fielding) and had an overall positive impact for his team.

But the other team had Denly moonlighting as their allrounder. Without even counting his fielding, he was involved in 87 balls - 36% of the match - making a hundred and taking 3 for 31; three quick wickets. In the two balls after dismissing Clarke, Denly got rid of Jamie Smith and Mathew Pillans. Clarke's dismissal was the start of a hat-trick and a fantastic collapse. Surrey needed 39 to win from 45 before Clarke was out. After he was out, they added 32.

Clarke bowled well, hit a six, and fielded fine. He more than did his job as an allrounder. But on one ball he made a mistake, and in T20 there is often no coming back. So 45 balls of good work was beaten by one mistake on the 46th , and it's that ball that leads to Surrey giving away the unlosable game.